Would you buy a tube amp if you were unable to use vintage tubes in it ?

I wouldn't, but I like equipment that is flexible as I gou through the adventure of finding my best sound. 

Soon there might be neither Chinese nor Russian new tubes available if the trade is stopped, so you better get a supply of them. Not my problem, I stay with vintage. You see, there is an unexpected advantage, in addition to expected advantage.

Back in the late ’90s I was running a Cary SLP-90  with 12au7s in front of a pair of ARC VTM-120s that were configured with four 6550s a piece with some 6922s in front of them.  I talked to Andy in Michigan and he sold me some NOS Mullard 12au7s for the pre and some NOS Amperex 6922s for the amps. After those tubes broke in a bit, that combination sounded fantastic.  At the time I was running the amps with Svetlanta 6550s (either the 6550b or 6550C, I cannot remember) and I was so happy with the results of the other tubes Andy sold me that I called Andy back again and this time he sold me two quads of either NOS or vintage used Tung-Sol 6550s.  Those cost me what I thought was an arm and a leg back then and I honestly couldn’t hear improvement.

I am not using the Cary right now and the ARCs are long gone; the stereo amp I am using right now takes a dozen EL34s and there is no way I am going to lay out what it would cost to go vintage used or NOS in that. 

Vintage used could be $100 each, but if you wanted to match dozen EL34 tubes..that would be a problem. And, yes, you couldn't be sure in advance of significant improvement. Well, vintage tubes were not created equal.

Bill, I use them for sound too but vintage tubes make me feel more, well, vintage ! And I like that. It's tradition and connection to the roots. Like tape and vinyl.

As for the cost, I made very approximate calculations that in the case of my amp I will have to spend about $50 per month on vintage tubes. Not the very best tubes available but high enough. Is this a lot ? It's nothing.